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the problem is that I have created a click event of link button category_Click and inside this click event I have created multiple dynamic controls and I created a click event of an image button Image_Click and now the issue is that the Category_Click event is firing but the Image_Click event is not firing. please help me.

aspx page code:-

 <%@ Page Title="" Language="C#" MasterPageFile="~/Homepage.Master" AutoEventWireup="true" CodeBehind="Categories.aspx.cs" Inherits="WebApplication1.Categories" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
    <link rel="Stylesheet" href="Genre.css" />
     <link rel="Stylesheet" href="genre_content.css" />
<asp:Content ID="Content2" ContentPlaceHolderID="categories" runat="server">
    <asp:Panel ID="Panel2" runat="server"></asp:Panel>   
<asp:Content ID="Content3" ContentPlaceHolderID="main" runat="server">
    <asp:Panel ID="Panel1" runat="server">
        <h2><asp:Label ID="Label1" class="h2" runat ="server" ></asp:Label></h2><br/>        
    <asp:Panel ID="Panel3" runat="server">
        <div class="data">          
                    <div class="image">
                        <asp:Image ID="Image1" runat="server" Cssclass="Img" />
                    <div class="description"> 
                        <asp:Label ID="Name" runat="server" class="name"></asp:Label>  
                        <asp:Label ID="Label2" runat="server" Text="(Paperback)"></asp:Label>
                        <div class="cos-shipping">
                            <div class="cos">
                                 Rs.<asp:Label ID="cost" runat="server" CssClass="co" ></asp:Label>
                            <div class="shipping">
                            <p>Ships within 4-6 Business Days</p>
                            <p>Rs.39 shipping in India per item and low cost Worldwide.</p>
                        <asp:Button ID="Button1" runat="server" Text="Buy Now" class="atc"/>
     <div class="details">
         <h2>Book Details</h2>
                        <asp:Label ID="about" runat="server" CssClass="about" ></asp:Label> 
                        <p>Author: <asp:Label ID="author" runat="server" ></asp:Label>   </p>   
                        <p>ISBN: <asp:Label ID="isbn" runat="server" ></asp:Label>     </p>                      
                        <p>Pubisher: <asp:Label ID="publisher" runat="server" ></asp:Label>  </p>
                        <p>No of pages: <asp:Label ID="nop" runat="server" ></asp:Label>           </p>
                        <p>Language: <asp:Label ID="language" runat="server" ></asp:Label>  </p>     
                        <p>Weight: <asp:Label ID="weight" runat="server" ></asp:Label>      </p>
                        <p>Available For :<asp:Label ID="available" runat="server" ></asp:Label>   </p>  

aspx.cs page code:-

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Web.UI.HtmlControls;

namespace WebApplication1
    public partial class Categories : System.Web.UI.Page
        private string ide, SQL, SQL2, label;
        private int num, i, num2, j;
        private ImageButton image;
        private LinkButton bookname;
        private Label money;
        private Label id;
        private Button wishlist;
        private LinkButton category;
        private static DataSet ds, ds2;
        private static SqlDataAdapter da, da2;
        private static HtmlGenericControl Book;
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
        SqlConnection con2 = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);

        protected void Page_Load(object sender, EventArgs e)
                Panel3.Visible = false;
                SQL2 = "Select distinct Book_category from Book_List";
                da2 = new SqlDataAdapter(SQL2, con2);
                ds2 = new DataSet();
                DataTable dt2 = new DataTable();
                num2 = ds2.Tables[0].Rows.Count;
                HtmlGenericControl header = new HtmlGenericControl("div");
                header.Attributes.Add("class", "header");
                for (j = 0; j < num2; j++)
                    category = new LinkButton();
                    category.Text = ds2.Tables[0].Rows[j]["Book_category"].ToString();
                    category.Attributes.Add("runat", "server");
                    category.Attributes.Add("CausesValidation", "false");
                    category.Click += new EventHandler(Category_Click);
        protected void Category_Click(object sender, EventArgs e)
            label = ((LinkButton)sender).Text;
            Label1.Text = label;
            SQL = "Select * from Book_List where Book_category='" + label + "'";
            da = new SqlDataAdapter(SQL, con);
            ds = new DataSet();
            num = ds.Tables[0].Rows.Count;
            //creating div element and putting all the elements ina  div called books
            Book = new HtmlGenericControl("div");
            Book.Attributes.Add("class", "books");
            for (i = 0; i < num; i++)
                //creating div element
                HtmlGenericControl myDiv = new HtmlGenericControl("div");
                myDiv.Attributes.Add("class", "myDiv");
                //creating image button
                image = new ImageButton();
                image.ImageUrl = ds.Tables[0].Rows[i]["Book_image"].ToString();
                image.CssClass = "Img";
                image.Attributes.Add("runat", "server");
                //image.UseSubmitBehaviour = false;
                image.Attributes.Add("CausesValidation", "false");
                //image.Attributes.Add("OnClick", "image_Click");
                //image.OnClientClick = Panel3;
               image.Click += new ImageClickEventHandler(Image_Click);
                //creating div inside myDiv
                HtmlGenericControl content = new HtmlGenericControl("div");
                content.Attributes.Add("class", "content");
                //creating a label to display id
                id = new Label();
                id.CssClass = "id";
                id.Text = ds.Tables[0].Rows[i]["Book_id"].ToString();
                id.Attributes.Add("runat", "server");
                //id.Click += new ImageClickEventHandler(id_Click);
                //creating a label for displaying name of the book
                bookname = new LinkButton();
                bookname.CssClass = "name";
                bookname.Text = ds.Tables[0].Rows[i]["Book_name"].ToString();
                bookname.Attributes.Add("runat", "server");
                //bookname.Click += new EventHandler(bookname_Click);
                //creating a label for displaying cost of the book
                money = new Label();
                money.CssClass = "cost";
                money.Text = "<br/> Rs " + ds.Tables[0].Rows[i]["Book_cost"].ToString();
                money.Attributes.Add("runat", "server");
                //creating a button to add the book to the wishlist
                wishlist = new Button();
                wishlist.Attributes.Add("runat", "server");
                wishlist.CssClass = "wishlist";
                wishlist.Text = "ADD TO WISHLIST";
        protected void Image_Click(object sender, ImageClickEventArgs e)
            Panel3.Visible = true;
            Panel2.Visible = false;
            //ImageButton image = sender as ImageButton;
            ide = ((ImageButton)sender).ImageUrl;
            for (i = 0; i < num; i++)
                if (ide == ds.Tables[0].Rows[i]["Book_image"].ToString())
                    Session["name"] = ds.Tables[0].Rows[i]["Book_name"].ToString();
                    Session["image"] = ds.Tables[0].Rows[i]["Book_image"].ToString();
                    Session["cost"] = ds.Tables[0].Rows[i]["Book_cost"].ToString();
                    Session["isbn"] = ds.Tables[0].Rows[i]["Book_isbn_no"].ToString();
                    Session["weight"] = ds.Tables[0].Rows[i]["Book_weight"].ToString();
                    Session["author"] = ds.Tables[0].Rows[i]["Book_author"].ToString();
                    Session["about"] = ds.Tables[0].Rows[i]["Book_about"].ToString();
                    Session["publisher"] = ds.Tables[0].Rows[i]["Book_publisher"].ToString();
                    Session["nop"] = ds.Tables[0].Rows[i]["No_of_pages"].ToString();
                    Session["language"] = ds.Tables[0].Rows[i]["Book_language"].ToString();
                    Session["available"] = ds.Tables[0].Rows[i]["Available_for"].ToString();
            Image1.ImageUrl = Session["image"].ToString();
            Name.Text = Session["name"].ToString();
            about.Text = Session["about"].ToString();
            cost.Text = Session["cost"].ToString();
            author.Text = Session["author"].ToString();
            isbn.Text = Session["isbn"].ToString();
            publisher.Text = Session["publisher"].ToString();
            nop.Text = Session["nop"].ToString();
            language.Text = Session["language"].ToString();
            weight.Text = Session["weight"].ToString();
            available.Text = Session["available"].ToString();

What I have tried:

I have tried using submit behaviour and causes validation but it didn't work I also tried creating all the dynamic elements in a function and then calling it but it gives a null error.
Updated 6-Apr-21 4:41am

1 solution

Page_Load is too late to create dynamic controls. You will overwrite the controls on every postback, so their events will never fire. Create the controls in Page_Init instead.

SQL = "Select * from Book_List where Book_category='" + label + "'";
Using string concatenation to build a SQL query can and will lead to SQL Injection[^].

NEVER use string concatenation to build a SQL query. ALWAYS use a parameterized query.

Everything you wanted to know about SQL injection (but were afraid to ask) | Troy Hunt[^]
How can I explain SQL injection without technical jargon? | Information Security Stack Exchange[^]
Query Parameterization Cheat Sheet | OWASP[^]
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